Steve Ramsey's Woodworking For Mere Mortals is one of my favorite YouTube channels. Not only is he funny, he's honest. This is a great example of a simple idea and the challenges you face in the middle of a project.
Say what you want about the decline of the bound paper book, but, as a someone who spends most of each day online as part of my full time job, I believe the internet, at least the parts where I interact, loves books and print media. Every day, I've see folks talking about books, making stuff with them, sharing their experience of reading them, and most interestingly, sharing awesome ways to store and display them.
Homeowner Mario and his wife Tete, from Sao Paulo, got inspired by a Tetris bookshelf he saw online, and started designing. His piece was custom fit into his space, built by a woodworking friend.
The shelf is 2.20 meters wide, 2 meters tall and 30 centimeters deep. It's made of MDF wood and the colored parts are Formica sheets.
As you can see in some of the pictures, all the parts are independent of each other so it's a modular project. I can unscrew half of the shelf and use it at another place or I can re-arrange the parts as I see fit (and the holes match too, it's a very artisan project!).